upload-pack: fix broken if/else chain in config callback

The upload_pack_config() callback uses an if/else chain
like:

if (!strcmp(var, "a"))
...
else if (!strcmp(var, "b"))
...
etc

This works as long as the conditions are mutually exclusive,
but one of them is not. 20b20a22f8 (upload-pack: provide a
hook for running pack-objects, 2016-05-18) added:

else if (current_config_scope() != CONFIG_SCOPE_REPO) {
... check some more options ...
}

That was fine in that commit, because it came at the end of
the chain.  But later, 10ac85c785 (upload-pack: add object
filtering for partial clone, 2017-12-08) did this:

else if (current_config_scope() != CONFIG_SCOPE_REPO) {
... check some more options ...
} else if (!strcmp("uploadpack.allowfilter", var))
...

We'd always check the scope condition first, meaning we'd
_only_ respect allowfilter when it's in the repo config. You
can see this with:

git -c uploadpack.allowfilter=true upload-pack . | head -1

which will not advertise the filter capability (but will
after this patch). We never noticed because:

- our tests always set it in the repo config

- in protocol v2, we use a different code path that
actually calls repo_config_get_bool() separately, so
that _does_ work. Real-world people experimenting with
this may be using v2.

The more recent uploadpack.allowrefinwant option is in the
same boat.

There are a few possible fixes:

1. Bump the scope conditional back to the bottom of the
chain. But that just means somebody else is likely to
make the same mistake later.

2. Make the conditional more like the others. I.e.:

else if (!current_config_scope() != CONFIG_SCOPE_REPO &&
!strcmp(var, "uploadpack.notallowedinrepo"))

This works, but the idea of the original structure was
that we may grow multiple sensitive options like this.

3. Pull it out of the chain entirely. The chain mostly
serves to avoid extra strcmp() calls after we've found
a match. But it's not worth caring about those. In the
worst case, when there isn't a match, we're already
hitting every strcmp (and this happens regularly for
stuff like "core.bare", etc).

This patch does (3).

Signed-off-by: Jeff King <peff@peff.net>
Reviewed-by: Josh Steadmon <steadmon@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/upload-pack.c b/upload-pack.c
index 87c6722ea58207a9b369e75f7cf7ac16a705330b..a47e4c2692e24085fdbf7f523b334bd193f17305 100644 (file)
--- a/upload-pack.c
+++ b/upload-pack.c
@@ -1070,12 +1070,15 @@ static int upload_pack_config(const char *var, const char *value, void *unused)
                keepalive = git_config_int(var, value);
                if (!keepalive)
                        keepalive = -1;
-       } else if (current_config_scope() != CONFIG_SCOPE_REPO) {
-               if (!strcmp("uploadpack.packobjectshook", var))
-                       return git_config_string(&pack_objects_hook, var, value);
        } else if (!strcmp("uploadpack.allowfilter", var)) {
                allow_filter = git_config_bool(var, value);
        }
+
+       if (current_config_scope() != CONFIG_SCOPE_REPO) {
+               if (!strcmp("uploadpack.packobjectshook", var))
+                       return git_config_string(&pack_objects_hook, var, value);
+       }
+
        return parse_hide_refs_config(var, value, "uploadpack");
 }